The protective effect of methanol extracts of Cassia fistula (flowers, leaves and bark) was examined in vitro in human umbilical vein endothelial cells (HUVEC) against toxicity induced by glycated protein (GFBS) in vitro. The experiments consisted of eight groups of HUVEC with five flasks in each group. Group I was treated with 15% FBS, group II with GFBS (70 microM) alone, and the other six groups were treated with GFBS plus 25 and 50 microg of each of the three types of C. fistula extracts. After 72 h of incubation, cells were collected and tested for lipid peroxidation, antioxidant enzyme activities and glutathione S-transferase (GST). The protective effect of C. fistula extracts against GFBS-induced cytotoxicity was examined in HUVEC by using trypan blue exclusion and MTT assays. Results showed that HUVEC incubated with GFBS alone showed a significant (P < 0.001) elevation of lipid peroxidation accompanied by depletion of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and glutathione reductase (GR), in addition to decreased cytosolic GST. Treatment of HUVEC with C. fistula extracts at a concentration of 25 and 50 microg significantly decreased lipid peroxidation and normalized the activities of the antioxidant enzymes and GST levels in a concentration-dependent manner. Morphological changes of HUVEC were compared with respective controls; in addition, the C. fistula extracts increased the viability of HUVEC damaged by GFBS. A protective effect of C. fistula extracts on HUVEC against GFBS-induced toxicity suggested a potential beneficial effect of the extract in preventing diabetic angiopathies.
Matched MeSH terms: Glycosylation End Products, Advanced/metabolism
OBJECTIVE: We previously reported ethnic disparity in adverse outcomes among Asians with type 2 diabetes (T2DM) in Singapore. Central arterial stiffness can aggravate systemic vasculopathy by propagating elevated systolic and pulse pressures forward, thereby accentuating global vascular injury. We aim to study ethnic disparity in central arterial stiffness and its determinants in a multi-ethnic T2DM Asian cohort.
METHODS: Arterial stiffness was estimated by carotid-femoral pulse wave velocity (PWV) and augmentation index (AI) using applanation tonometry method in Chinese (N = 1045), Malays (N = 458) and Indians (N = 468). Linear regression model was used to evaluate predictors of PWV and AI.
RESULTS: PWV was higher in Malays (10.1 ± 3.0 m/s) than Chinese (9.7 ± 2.8 m/s) and Indians (9.6 ± 3.1 m/s) (P = 0.018). AI was higher in Indians (28.1 ± 10.8%) than Malays (25.9 ± 10.1%) and Chinese (26.1 ± 10.7%) (P < 0.001). Malays remain associated with higher PWV (β = 0.299, P = 0.048) post-adjustment for age, gender, duration of diabetes, hemoglobin A1c, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), soluble receptor for advanced glycation end-products, urinary albumin-to-creatinine ratio, and insulin usage, which were all independent predictors of PWV. Indians remain associated with higher AI (β = 2.776, P < 0.001) post-adjustment for age, gender, BMI, SBP, DBP, and height, which were independent predictors of AI. These variables explained 27.7% and 33.4% of the variance in PWV and AI respectively.
CONCLUSIONS: Malays and Indians with T2DM have higher central arterial stiffness, which may explain their higher risk for adverse outcomes. Modifying traditional major vascular risk factors may partially alleviate their excess cardiovascular risk through modulating arterial stiffness.
KEYWORDS: Arterial stiffness; Augmentation index; Pulse wave velocity; Type 2 diabetes
Matched MeSH terms: Glycosylation End Products, Advanced/blood
BACKGROUND: The role of endothelial injury and circulating adhesion molecule in the development and progression of diabetic peripheral neuropathy in the long-term has been established previously.
AIMS: To study the effects of short-term glycemic control using insulin and oral hypoglycemic agent therapy (OHA) on the peroneal nerve function and vascular cell adhesion molecule-1 (VCAM-1) and advanced glycation endproducts (AGE) levels in type 2 diabetic patients.
SETTINGS AND DESIGN: A randomized controlled study involving poorly controlled (HbA1c, 7.5%-11%) type 2 diabetic patients attending the endocrinology outpatient center in a tertiary hospital in Kuala Lumpur.
MATERIALS AND METHODS: Twenty-nine patients were randomized to receive insulin (n=15) or OHA (n=14) for 8 weeks. The glycemic variables (HbA1c, fasting plasma glucose [FPG], fructosamine), VCAM-1, serum AGE and the peroneal motor conduction velocity (PMCV) were measured at baseline and at 4-week intervals.
STATISTICAL ANALYSIS USED: Paired 't' test or Kruskal Wallis test; and the unpaired 't' test or Mann-Whitney U test were used for within-group and between-group analyses, respectively. Correlation was analyzed using Spearman's correlation coefficient.
RESULTS: Within-group analysis showed significant progressive improvement in HbA1c at weeks 4 and 8 in the insulin group. The PMCV improved significantly in both groups by week 8, and by week 4 (P = 0.01) in the insulin group. PMCV correlated negatively with VCAM-1 (P = 0.031) and AGE (P = 0.009) at week 8.
CONCLUSION: Aggressive glycemic control with insulin improves the peroneal nerve function within 4 weeks. Improvement in the serum VCAM-1 and AGE levels correlated significantly with improvement in peroneal nerve conduction velocity only in the insulin group.
Study site: Tertiary endocrinology outpatient center in Kuala Lumpur, Malaysia
Matched MeSH terms: Glycosylation End Products, Advanced/blood